1. Field of the Invention
This invention pertains to industrial vibrators of the type used in the bulk material handling industry, as well as other industries. More particularly, this invention pertains to a rotary industrial vibrator device having repositionable eccentric weights and to methods for extending the useful life of such rotary vibratory devices. The eccentric weights can be repositioned relative to the rotor shaft simply by inverting or shifting the phase or voltage of the power supplied to the vibrator. Repositioning the weights changes the location of maximum bearing wear and thereby extends the life of the vibrator.
2. General Background
Industrial vibrators are used throughout the bulk material handling industry for various purposes. Such industrial vibrators are often attached to bulk material transfer chutes and bulk material storage hoppers to prevent bulk material from clinging to the walls of such chutes and hoppers. Industrial vibrators are also utilized on sifting screens to prevent larger material from clogging the sifting screens and to speed the flow of material passing through the screens.
A common type of vibratory device is the rotary vibratory motor, wherein eccentric weights are rotationally driven by, and rotate about, a shaft axis via an electric motor to thereby generate oscillating forces. Other types of vibratory devices include, but are not limited to, acoustical vibration devices, air driven rotary vibrators, and linear vibrators. The present invention pertains specifically to electric driven eccentric weight vibrators.
In rotatory vibratory devices, the forces generating in by the rotating eccentric weights are transmitted to the motor housing via the bearings that support the rotor shaft. In view of the eccentricity of the weights, the bearing forces acting on the rotary shaft peak on the side of the bearing shaft that is closest to the center of mass of the eccentric weights, while the opposite side of the rotor shaft sees little, if any, bearing load. As a result, the portion of the bearing surface of the shaft closest to the center of mass of the eccentric weights wears at the greatest rate.